2Trapping the Sun’s Energy The process by which plants capture energy from the sun to build carbohydrates through chemical pathways is called photosynthesisSolar energy converts water and carbon dioxide into chemical energy stored in simple sugarsThe simple sugar that photosynthesis produces is glucose which the plant uses to store energy.The equation that represents photosynthesis is:6CO2 + 6H2O C6H12O6 + 6O2Solar energy
3Comparing Autotrophs and Heterotrophs Chapter 6Section 1 The Light ReactionsComparing Autotrophs and HeterotrophsClick below to watch the Visual Concept.Visual Concept
4Phases of Photosynthesis Photosynthesis requires energy from the sun, but the sun is not available 24 hours a day.Photosynthesis must occur in two phasesLight-dependent Reactions (light reactions)Convert light energy into chemical energy (ATP and NADPH)Light-independent Reactions (dark reactions)Uses the ATP and NADPH from the light-dependent reactions to build glucose6CO2 + 6H2O C6H12O6 + 6O2Solar energy
5The Role of Chloroplasts and Pigments Photosynthesis takes place in the chloroplastsLight-dependent reactions take place in the membranes of the thylakoid disks (contain chlorophyll)Light-independent reactions take place in the stroma (thick fluid that forms the framework of a chloroplast)
6The Role of Chloroplasts and Pigments The thylakoid membranes contain the pigments that can absorb certain wavelengths of sunlight.The most common pigment in the chloroplasts is chlorophyll.Chlorophyll a and b absorb most wavelengths of light except for green. Green is reflected making the plants appear green.In the fall, plants reabsorb chlorophyll leaving other pigments that reflect other wavelengths of light – making the leaves appear red, yellow, or orange.
7Spectrum of Light and Plant Pigments Chapter 6Section 1 The Light ReactionsSpectrum of Light and Plant PigmentsClick below to watch the Visual Concept.Visual Concept
8Light-dependent Reactions Sunlight strikes the chlorophyll molecules in the thylakoid membrane.Light energy is transferred to electronsThe electrons become highly energized and are passed down an Electron Transport Chain
9Light-dependent Reactions The Electron Transport Chain is a series of proteins in the thylakoid membraneAs the electrons are transferred from one protein to another, some energy is released whichhelps join ADP and Phosphate to form ATPPump hydrogen ions into the center of the thylakoid disk to join H+ and NADP+ forming NADPH (electron carrier)ATP and NADPH will be used during the light-independent reactions
10Light-dependent Reactions The electrons excited by the light energy that passed down the electron transport chain and left with NADPH need to be replaced so the reaction can happen again.To replace those electrons, a water molecule is split (photolysis), sending electrons back to the chlorophyll and releasing Oxygen and Hydrogen ions into the atmosphere – this supplies the oxygen that we breathePhotolysis
11Light-dependent Reactions Solar Energy absorbed by chloroplastsOxygen releasedATP ReleasedProducts of Light Reactions (ATP and NADPH) fuel the dark reactionsNADPH released
12Light-independent Reactions The second phase of photosynthesis does not require light and is called the Calvin Cycle.The Calvin Cycle occurs in the stroma of the chloroplast.The Calvin Cycle uses the ATP and NADPH that was built during the light-dependent reactions
13The Calvin Cycle Uses Carbon Dioxide from the air Uses ATP and NADPH from light reactionsUses another ATP to replenish RuBPBuilds a glucose molecule
14Photosynthesis Equation Light Energy6CO2 + 6H2O C6H12O6 + 6O2chlorophyllCarbon Dioxide from the air – Used in the Calvin Cycle during the Dark ReactionsGlucose Made in the Calvin Cycle during the Dark ReactionsOxygen Released during Photolysis in the Light ReactionsWater Split during Photolysis in the Light ReactionsPlants can use this glucose molecule for energy during Cellular Respiration. Plants can also convert this glucose molecule into other organic compounds such as proteins and fats/lipids or other carbohydrates like starch and cellulose
153 Factors that Affect Photosynthesis Carbon Dioxide (CO2)Without CO2, the plant would not have one of the raw materials needed in the photosynthesis equationCO2 is used in the first step of the Calvin CycleTemperatureThe temperature must be in the appropriate range for the plant in order for photosynthesis to properly occur
163 Factors that Affect Photosynthesis Intensity of LightIf the intensity of light is lower, the available energy for photosynthesis is lower.In a greenhouse, if the light source is further away, intensity is lower and less photosynthesis can occurIf light is not available at all, the light-dependent reactions cannot occur (nor can they provide the materials used in the light-independent reactions)
17Environmental Influences on Photosynthesis Chapter 6Section 2 The Calvin CycleEnvironmental Influences on PhotosynthesisClick below to watch the Visual Concept.Visual Concept
18Nutrients + oxygen water + ATP + CO2 Cellular RespirationCellular Respiration: Process by which mitochondria break down food molecules to produce ATP in plants and animalsNutrients + oxygen water + ATP + CO2Changes organic chemical energy (glucose) into inorganic chemical energy (ATP)There are three stages of Cellular RespirationGlycolysisAnaerobic – does not require oxygenCitric Acid (Krebs) CycleAerobic – does require oxygenElectron Transport Chain
19GlycolysisGlycolysis: Breaks down glucose into two molecules of pyruvic acid (a colorless acid formed as an important intermediate in metabolism or fermentation)This reaction uses enzymes and takes place in the cytoplasm of the cell (anaerobic reaction)Produces2 pyruvic acid molecules (used in the next step of Cellular Respiration)2 ATP molecules (energy the cell can use)2 NADH (electron carrier)
20Glycolysis Chapter 7 Section 1 Glycolysis and Fermentation Click below to watch the Visual Concept.Visual Concept
21Into the Mitochondria… Before the next step of Cellular Respiration can occur, the pyruvic acid molecules must go into the mitochondriaThe two oxygen-dependent (aerobic) reactions are the Citric Acid Cycle (or Krebs Cycle) and the electron transport chainPyruvic acid CO2 + water + ATP
22Citric Acid/Krebs Cycle (see page 138 in your book) CO2 is releasedPyruvate from Glycolysis fuels the cycleCO2 is releasedNADH and FADH2 is releasedATP is released
23Electron Transport Chain Electron Transport Chain uses the electron carriers (NADH and FADH2) to pass electrons down the protein chain and slowly release energy that is used to form ATP and water moleculesElectron Transport Chain transfers the most energy
24Electron Transport Chain Cellular RespirationATPGlycolysisGlucosePyruvic AcidCO2Citric Acid CyclePyruvic AcidATPNADH and FADHWaterNADH and FADHElectron Transport ChainOxygenATP
25Cellular Respiration Equation C6H12O6 + 6O CO2 + 6H2O + energyCarbon Dioxide – waste product of the Citric Acid CycleWater – released from Electron Transport ChainGlucose made in photosynthesis by plants or consumed by animalsUsed in GlycolysisATP released from Glycolysis, Citric Acid Cycle, and Electron Transport ChainOxygen from the atmosphere Used in Electron Transport ChainBetween ATP can be made with this process. This ATP can be used by the cells for cellular metabolism.
26FermentationWhen oxygen is not available anaerobic respiration, fermentation, can follow glycolysis in order to continue to produce energy.This is not as efficient as aerobic respiration and produces far fewer ATP’sTwo types of fermentation:Lactic acid FermentationAlcoholic Fermentation
27Lactic acid Fermentation Lactic acid fermentation occurs in muscle cells during strenuous exercise when a lot of energy is required and oxygen is scarce (oxygen debt).Glucose pyruvic acid lactic acid + ATPThe lactic acid is transferred from the muscle cells to the liver where it will be converted back into pyruvic acidThe build up of lactic acid in the muscles is what causes them to be fatigued and sore.
28Alcoholic Fermentation Yeast and some bacteria cells are capable of alcoholic fermentation during which glucose is broken down to release CO2 and ethyl alcoholGlucose pyruvic acid alcohol + CO2 + ATPThe bubbles formed by the CO2 make bread riseThe alcohol released turns grape juice into wine
29Comparing Aerobic and Anaerobic Respiration Section 1 Glycolysis and FermentationChapter 7Comparing Aerobic and Anaerobic RespirationClick below to watch the Visual Concept.Visual Concept
30Photosynthesis vs. Cellular Respiration Stores Energy as glucoseReleases Energy in glucoseOccurs in Living CellsUses an Electron Transport ChainOccurs in Plant CellsOccurs in Animal CellsReleases OxygenReleases Carbon DioxideCreates EnergyNeither!